Update git submodules

* Update docs/submodules/sfc from branch 'master'
  - Clean up our utils.py

    Utils.py was getting messy. This patch divides it into three different files:

    * test_utils.py
    * odl_utils.py
    * openstack_utils.py

    The tacker library is integrated into openstack_utils.py

    Change-Id: I310949d1cee49b6aa1c9b3396bf6d6ca458cbaac
    Signed-off-by: Manuel Buil <mbuil@suse.com>

diff --git a/docs/submodules/sfc b/docs/submodules/sfc
index 8814891..d4757d2 160000 (submodule)
--- a/docs/submodules/sfc
+++ b/docs/submodules/sfc
@@ -1 +1 @@
-Subproject commit 8814891148390d427c22e583b2d7451dbd600197
+Subproject commit d4757d239155cbd21ce45b656469c10d67cdf569